Response of bacterial community structure in saline soils to the application of kitchen waste-derived fermented organic fertilizer.

Saline soils, which inhibit plant growth and diminish soil functions such as carbon storage, present a significant challenge to agricultural productivity. Consequently, soil improvement is crucial for achieving sustainable agricultural development. Organic fertilizers, particularly those derived from kitchen waste, have shown potential in enhancing soil fertility and structure. However, the interaction between kitchen waste - derived fermented organic fertilizers and their impact on microbial diversity, community structure, and nutrient dynamics in saline soils remains an underexplored area within environmental research. In this study, microcosm experiments were conducted with saline soil samples. We examined the temporal changes in soil nutrient levels and microbial diversity after the application of inorganic and organic fertilizer for a 15-day period. The results demonstrated that short-term application of kitchen waste fermented organic fertilizer significantly increased the levels of organic matter (OM), total nitrogen (TN), hydrolyzed nitrogen (HN), total phosphorus (TP), available phosphorus (AP), and available potassium (AK); however, it also led to a reduction in microbial diversity within saline soils while simultaneously promoting the presence of beneficial microorganisms such as Photobacterium, Pseudoalteromonas, and Planococcus. The relative abundance of Bacillus increased from 0.34 to 35.22% in the COS (treatment with 30% organic fertilizer) treatment. The redundancy analysis demonstrated that, except for TK (total potassium), the physicochemical properties of the saline soils were positively correlated with the dominant bacterial community abundance under the BOS (treatment with 10% organic fertilizer) and COS treatments but negatively correlated with the salt-tolerant bacterial abundance under the CK (treatment with saline soil) and AIS (treatment with saline soil and inorganic fertilizer) treatments. In conclusion, the application of kitchen waste fermented organic fertilizer is a beneficial strategy for enhancing saline soil fertility, promoting the proliferation of beneficial microorganisms, and rehabilitating saline soils.